Abstract

Based on the unique geometrical structure of nanotetra-ZnO needle , we investigate the microwave responses of , including interface scattering, microcurrent attenuation, microantenna radiation, and dielectric relaxation, and build an energy attenuation model. The associated quantitative formula is deduced for calculating the microwave absorption properties of nanocomposite in the range 8–14 GHz according to the present energy attenuation model. Very good agreement between the calculated and experimental results is obtained in a wide frequency range. The maximum deviation less than 0.5 dB in the range 8–14 GHz is obtained. Using the aforementioned model, we analyze the contribution of microwave responses to the energy attenuation in the frequency range 2–18 GHz, and the results reveal that interface scattering and microcurrent attenuation make the contribution most important. In addition, we calculate the effects of the volume fraction, conductivity, permittivity, needle length of , and thickness of on the reflectivity. The results show that the microwave absorption is evidently dependent on these effect factors, and the optimal microwave absorption band and the strongest microwave absorption peak of would appear when these physical parameters are changed.

Received 06 September 2009Accepted 22 December 2009Published online 02 March 2010

Acknowledgments:

This work is supported by the National Natural Science Foundation of China under Grant Nos. 50572010, 50972014, and 50872159; the National Defense Funds of China under Grant No. A2220061080; and the National High-Technology Research and Development Program of China under Grant No. 2007AA03Z103. The authors also thank Editor J. L. Wu for revising the manuscript. X. Y. Fang, M. S. Cao, and J. Yuan contributed equally to this work.

Article outline:I. INTRODUCTIONII. EXPERIMENTAL DETAILSIII. MICROWAVEATTENUATION MODELA. Responses of a single 1. The interface scattering response2. The microcurrent response3. The dielectric relaxation response4. The microantenna responseB. Energy attenuation model of a single C. Reflectivity calculation model of nanocompositeIV. COMPARISON AND ANALYSIS OF FOUR RESPONSESV. CALCULATION AND PREDICTIONVI. CONCLUSION